Apparatus for generating an electrocardiogram

ABSTRACT

Wrist-wearable apparatuses that may be removed and used as a chest-applied cardiac device may include two chest electrodes on an inner surface of a strap (or strap regions), as well as two finger or more finger electrodes on the opposite side of the apparatus. The apparatus may be removed from the wrist and placed on a chest of a patient such that two electrodes are spaced at least five centimeters apart and in contact with the chest and held in place with two or more fingers to capture orthogonal cardiac signals that may be synthesized into a conventional 12-lead cardiac signal.

CLAIM OF PRIORITY

None.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

BACKGROUND

Handheld electrocardiogram (ECG) devices may be used by a patient (or amedical professional) to capture and record ECG data. Unfortunately,despite the potential benefit to such hand-held apparatuses, none havefound widespread use. This may be due in part, to the size, weight andease of use, as well as the need to carry and apply the apparatus duringthe day, which may be inconvenient, and disruptive. Although devicesthat may be worn continuously that may track ECG have also beenproposed, these devices may be uncomfortable and/or may have a lowaccuracy, particularly if measuring device from regions other than thechest.

Therefore, there is a need for a compact ECG device that is capable ofcapturing cardiac signals from the chest that are easy to use,convenient and still highly accurate.

SUMMARY OF THE DISCLOSURE

The methods and apparatuses (e.g., systems, devices, etc.) describedherein may relate generally to electrocardiography.

In general, described herein are methods and apparatuses for recordingand analyzing cardiac signals from a patient using a wrist worn ECG‘watch’ device (or more generally, a w wrist-worn device) that may betaken off of the wrist and held against the subject's chest by thesubject. The apparatus is configured so that, when removed from thesubject's wrist, it may assume a configuration that may be easily andaccurately placed against the chest and held by the subject to providethree orthogonal leads that may be used to generate a synthetic 12 leadECG signal that comports with traditional 12-lead ECG signals and may beeasily read by those trained in standard electrocardiograms.

These apparatuses may typically include a strap (which in some exampleshas multiple strap regions) that and a housing (including a display).When not used to record ECG signals on the subject's chest, theapparatus may be a wrist-worn device that may display the time and/orother information (e.g., heart rate/pulse, blood oxygenation,steps/movement, etc.). In some examples the apparatus may be configuredas a smartwatch (e.g., phone, etc.) or any other wrist-worn device. Theapparatus may include a first configuration that is configured as awrist-worn strap that may be secured to the subject's wrist. At leasttwo electrodes may be on the inner surface (of the strap and/or housing)and at least two electrodes may be positioned on an outer surface (e.g.,on the strap and/or housing). The inner electrodes are configured sothat when the apparatus is removed from the wrist, and transitioned to alinear configuration the inner electrodes may be separated from eachother by a predefined distance, e.g., of greater than 5 cm (greater than6 cm, greater than 7 cm, greater than 8 cm, greater than 9 cm, greaterthan 10 cm, greater than 11 cm, etc.), e.g., between 6 and 14 cm (e.g.,between 6 and 13 cm, between 6 and 12 cm, between 6 and 11 cm, between 8and 10 cm, etc.). The inner (chest) electrodes may provide cardiac leadsignals in combination with the outer (hand/finger) electrodes and mayprovide a set of orthogonal three-lead cardiac signals.

As used herein, a cardiac signal may refer to a voltage produced by ahuman heart as sensed between selected points on the surface of asubject's body and may also be referred to as cardiac electrical signals(e.g., electrocardiac signals). These cardiac signals may includeelectrocardiogram (ECG) signals. It should be understood that althoughthe term ECG (electrocardiogram) is commonly used to refer toconventional 12-lead ECG signals, the cardiac signals (cardiacelectrical signals) described herein are not limited to theseconventional 12-lead ECG signals.

Described herein are mobile, hand-held devices for capturing cardiacsignals. The device may include a first electrode on an inner surface ofa first wrist band region, and a second electrode on an inner surface ofa second wrist band region (or in some examples a housing). The secondwrist band region may be on a separate wrist band, or it may be a secondregion of the same wrist band as the first wrist band region. The thirdand fourth electrodes are configured to be contacted by a finger of afirst and second hand, respectively, when the apparatus is held by thesubject against the subject's chest. In some cases the subject, whichmay be a patient or user, may hold the unbuckled/unfastened apparatusafter removing it from the wrist, in a linear configuration against thesubject's chest.

In some examples the apparatus includes a first wrist band region thatis part of a first wrist band that is configured to removably couple toa second wrist band region that is part of a second wrist band. Thedevice may also include a housing coupled to the first wrist band andthe second wrist band, where the first wrist band, the second wristband, and the housing are configured to form a continuous loop to beworn on a wrist. The housing may include electrical circuits configuredto receive electrical signals from the first, second, third, and fourthelectrodes, and determine a set of three-lead cardiac signals from theelectrical signals, wherein the set of three-lead cardiac signalsinclude sufficient information to synthesize (e.g., determine, derive)conventional 12-lead electrocardiogram (ECG) information. The housingmay also include a processor and/or other circuitry as descried hereinfor recording and/or analyzing an ECG signal. The housing may alsoinclude circuitry for a clock/watch that may be shown on a display. Thesame processor and circuitry may be used and/or integrated with thecircuitry for measuring, analyzing, storing and transmitting the ECGsignals as described herein (including the 3 orthogonal leads).

Any of the devices may include a first electrode and a second electrodeconfigured to contact a patient's chest. Furthermore, in any of thedevices described herein the first electrode and the second electrodemay be configured to be separated by a distance of at least fivecentimeters when the first electrode and the second electrode arereceiving electrical signals from a patient's heart.

In any of the devices described herein, a third electrode may beconfigured to be placed in contact with a finger from a first hand andthe fourth electrode may be configured to be placed in contact with afinger from a second hand, the second hand being different than thefirst hand. Furthermore, in any of the devices described herein, theelectrical circuits may be further configured to record one or more setsof three-lead cardiac signals.

In the devices described herein, the apparatus, including in some casesthe electrical circuits within the housing, may be further configured togenerate conventional 12-lead ECG information from at least one set ofthree-lead cardiac signals. Alternatively, in some examples theapparatus may be configured so that an external or remote processor isused to generate conventional 12-lead ECG information from the recordedsignals (e.g., forming 3 orthogonal leads). Furthermore, in theapparatuses (e.g., devices, systems, etc. including wrist-worn devicesand/or watches) described herein, the apparatus may include a housingfurther comprises a display configured to display instructions tocapture one or more sets of three-lead cardiac signals with the device.The display may be configured to display the time or other informationduring operation of the apparatus as a watch when worn encircling thewrist. In some examples the housing may include a display configured todisplay instructions to capture one or more sets of three-lead cardiacsignals with the device. In some examples, the housing may additionallyor alternatively include a speaker configured to provide audibleinstructions to capture one or more sets of three-lead cardiac signalswith the device.

In any of the apparatuses described herein, the device may include atransmitter configured to transmit one or more sets of three-leadcardiac signals to a second device. Furthermore, the first wrist bandmay include conductors to electrically couple the first electrode andthe second electrode to the electrical circuits and the second wristband may include conductors to electrical couple the third electrode andthe fourth electrode to the electrical circuits.

In some examples a wearable cardiac diagnosis device is described. Thewearable cardiac diagnosis device may comprise a first wrist band regionincluding a first electrode, a second wrist band region including asecond electrode, and a third and a fourth electrode on an outer surfaceof the apparatus, and the apparatus is configured to removably couple tothe first wrist band region to the second wrist band region and to forma continuous band to be worn on a subject's wrist. The apparatus mayinclude a housing may that be coupled to the first wrist band region andthe second wrist band region and may include a display, and in someexamples electrical circuits configured to operate in a first mode todisplay time of day information on the display and operate in a secondmode to receive electrical signals from the first, second, third, andfourth electrodes, and determine a set of three-lead cardiac signalsfrom the electrical signals.

In any of the wearable apparatuses described herein, the set ofthree-lead cardiac signals may include sufficient information tosynthesize conventional 12-lead electrocardiogram (ECG) information. Insome examples, the first electrode and the second electrode may beconfigured to be separated by at least 5 centimeters and simultaneouslycontact a chest of a patient. In some examples, the third electrode maybe configured to receive a first cardiac signal from a finger of a firsthand and the fourth electrode may be configured to receive a secondcardiac signal from a finger of a second hand different from the firsthand.

In any of the wearable apparatuses described herein, the housing mayfurther enclose a wireless transmitter configured to transmit three-leadcardiac data when the wearable cardiac diagnosis device is operating inthe second mode. In some examples, the apparatuses may be configured todisplay instructions to capture one or more sets of three-lead cardiacsignals when the wearable cardiac diagnosis device is operating in thesecond mode.

In any of the apparatuses described herein, the apparatus may beconfigured to display information regarding electrode placement when thewearable device is operating in the second mode. The housing may furtherenclose a speaker configured to provide audible instructions to captureone or more sets of three-lead cardiac signals when the wearable cardiacdiagnosis device is operating in the second mode.

This patent application may be related to U.S. patent application Ser.No. 17/092,152, titled “MOBILE THREE-LEAD CARDIAC MONITORING DEVICE ANDMETHOD FOR AUTOMATED DIAGNOSTICS,” filed on Nov. 6, 2020, and U.S.patent application Ser. No. 17/443,456, titled “ELECTROCARDIOGRAM PATCHDEVICES AND METHODS,” filed on Jul. 26, 2021, and U.S. patentapplication Ser. No. 17/570,368, titled “ELECTROCARDIOGRAM PATCH DEVICESAND METHODS,” filed on Jan. 6, 2022, each of which is hereinincorporated by reference in its entirety.

For example, described herein are wrist-worn apparatuses configured tomeasure 12-lead ECG signals, apparatus comprising: a first wrist bandportion including a first electrode on an inner side of the first wristband portion and a third electrode on an opposite side of the firstwrist band portion; a second wrist band portion including a secondelectrode on an inner side of the second wrist band portion and a fourthelectrode on an opposite side of the second wrist band portion, whereinthe first wrist band portion and second wrist band are configured toform a continuous loop worn on a subject's wrist, and are furtherconfigured to be spread apart and positioned on the subject's chest sothat the first electrode and the second electrode are separate bybetween 6 and 14 cm to measure bioelectric signals from the subject'schest, wherein the third electrode is configured to measure bioelectricsignals from the subject's right hand and the fourth electrode isconfigured to measure bioelectric signals from the subject's left hand;a resistive network forming a central point in a sagittal plane throughthe subject's chest passing between the third and fourth electrodes whenthe first wrist band portion and the second wrist band portion are heldagainst the subject's chest, wherein three orthogonal cardiac leads areformed from the first, second, third and fourth electrodes and thecentral point; and a processor configured to process the threeorthogonal cardiac leads derived from the first, second, third andfourth electrodes.

The third electrode may be configured to be placed in contact with afinger from the subject's first hand and the fourth electrode isconfigured to be placed in contact with a finger from the subject'ssecond hand, the subject's second hand being different than thesubject's first hand.

The processor may be configured to record and transmit the threeorthogonal cardiac leads. The processor may be configured to synthesizeconventional 12-lead electrocardiogram (ECG) information from the threeorthogonal leads. The processor may be housed within a housingpositioned between the first wrist band portion and the second wristband portion.

As mentioned, any of these apparatuses may include a housing enclosingthe resistive network and processor, wherein the housing is positionedbetween the first wrist band portion and the second wrist band portion.

Any of these apparatuses may include a display configured to display atime output when the first wrist band portion and the second wrist bandform a continuous loop worn on a subject's wrist. The display may beconfigured to indicate an orientation of the apparatus when held againstthe subject's chest. Any of these apparatuses may include a claspconfigured to secure the first wrist band portion to the second wristband portion around the subject's wrist.

The apparatus may include a wireless transmitter configured to transmitdata from the three orthogonal cardiac leads.

The processor may be configured to output instructions to capture one ormore sets of three-lead cardiac signals when the first wrist bandportion and second wrist band are spread apart.

For example, a wrist-worn apparatus configured to measure 12-lead ECGsignals may include: a first wrist band portion including a firstelectrode on an inner side of the first wrist band portion and a thirdelectrode on an opposite side of the first wrist band portion; a secondwrist band portion including a second electrode on an inner side of thesecond wrist band portion and a fourth electrode on an opposite side ofthe second wrist band portion, wherein the first wrist band portion andsecond wrist band are configured to form a continuous loop worn on asubject's wrist, and are further configured to be spread apart andpositioned on the subject's chest so that the first electrode and thesecond electrode are separate by between 6 and 14 cm to measurebioelectric signals from the subject's chest, wherein the thirdelectrode is configured to measure bioelectric signals from thesubject's right hand and the fourth electrode is configured to measurebioelectric signals from the subject's left hand; a housing coupledbetween the first wrist band portion and the second wrist band portioncomprising a display face; a resistive network with the housing andforming a central point in a sagittal plane through the subject's chestpassing between the third and fourth electrodes when the first wristband portion and the second wrist band portion are held against thesubject's chest, wherein three orthogonal cardiac leads are formed fromthe first, second, third and fourth electrodes and the central point;and a processor configured to process the three orthogonal cardiac leadsderived from the first, second, third and fourth electrodes and tosynthesize conventional 12-lead electrocardiogram (ECG) information fromthe three orthogonal cardiac leads.

Also described herein are methods of detecting a cardiac signal from asubject, the method comprising: removing a wrist-worn apparatus from thesubject's wrist; placing a first wrist band portion of the wrist-wornapparatus against the subject's chest so that a first electrode on aninner surface of the first wrist band portion is in contact with thesubject's chest and a second electrode on an inner surface of a secondwrist band portion against is in contact with the subject's chest,wherein the first electrode is separated from the second electrode bybetween about 6 cm and 12 cm; placing a finger of a first hand against athird electrode on an outer surface of the wrist-worn apparatus and anfinger of a second hand against a fourth electrode of the wrist-wornapparatus; and measuring three orthogonal leads using a resistivenetwork forming a central point in a sagittal plane through thesubject's chest passing between the third and fourth electrodes when thefirst wrist band portion and the second wrist band portion are heldagainst the subject's chest, wherein three orthogonal cardiac leads areformed from the first, second, third and fourth electrodes and thecentral point; processing the three orthogonal cardiac leads tosynthesize conventional 12-lead electrocardiogram (ECG) information; andoutputting the conventional 12-lead ECG information.

Any of these methods may include removing the wrist-worn apparatus fromthe subject's wrist by uncoupling a latch on the wrist-worn apparatus.Any of these methods may include transmitting the three orthogonalcardiac leads from the wrist-worn apparatus to a remote processor toprocess the three orthogonal leads.

Placing the finger of the first hand against the third electrode maycomprise placing the finger of the first hand against the thirdelectrode on an outer surface of the first wrist band portion andplacing the finger of the second hand against the fourth electrodecomprises placing the finger of the second hand against the fourthelectrode on an outer surface of the second wrist band portion. In someexamples placing the finger of the first hand against the thirdelectrode comprises placing the finger of the first hand against ahousing comprising a display, wherein the housing is between the firstwrist band portion and the second wrist band portion.

Processing the three orthogonal leads may comprise processing the usinga processor housed within a housing positioned between the first wristband portion and the second wrist band portion. Any of these methods mayinclude display a time output on a display of the wrist-worn apparatuswhen the wrist-worn apparatus is worn on the subject's wrist.

The methods described herein may include instructing the subject, via anoutput from the wrist-worn apparatus, how to hold the wrist-wornapparatus against the subject's chest.

Any of the methods and apparatuses described herein may be configured tomonitor the patient's cardiac activity while wearing the apparatus onthe wrist, and may alert the wearer (or a caregiver) to take a chestrecording with the apparatus if the apparatus detects activity thatexceeds a monitoring threshold. For example, any of these apparatusesmay include one or more sensor, e.g., electrodes, optical sensors (e.g.,Photoplethysmography or PPG sensors), etc., and may include software,hardware or firmware, e.g., as part of a controller, to monitor theoutput of the sensor periodically (e.g., about every x minutes, where xis 0.1, 0.2, 0.25, 0.3, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40,45, 60, etc.) or continuously to determine if the sensed signal fallswithin a range or has a pattern characteristic of a cardiac problem. Theapparatus may make an alert on the wrist-worn apparatus, by one or moreof; displaying a message (text, graphic, etc.), flashing a light,emitting a tone, etc. In some examples the apparatus may send a message(e.g., SMS message/text message, email, etc.) to the wearer and/orcaregiver. In some examples the message may include a recommendation orinstructions that a “chest recording is advised”. Thus, any of theseapparatuses may include a monitoring mode when the apparatus is worn onthe wrist. The apparatus may be configured to enter the monitoring modemanually or automatically, such as when the apparatus senses that thedevice is being worn on the wrist by a user.

All of the methods and apparatuses described herein, in any combination,are herein contemplated and can be used to achieve the benefits asdescribed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the features and advantages of the methods andapparatuses described herein will be obtained by reference to thefollowing detailed description that sets forth illustrative examples,and the accompanying drawings of which:

FIG. 1A illustrates one example of a system for cardiac signal detectionand/or diagnosis.

FIG. 1B shows a view of another example of a system for cardiac signaldetection.

FIGS. 2A, 2B and 2C show front, back and axonometric views,respectively, of an example of a handheld device.

FIG. 2D shows a front view of a device placed against the patient's bodyin a recording position.

The example in FIG. 3A shows a simple electrical scheme for obtaining acentral point (CP) signal by connecting the electrodes of both hands viaa simple resistive network consisting of two resistors.

FIG. 3B shows an electrical scheme for obtaining the CP signal usingbuffering and averaging via operational amplifiers.

FIG. 4A shows a front view of an example of a wrist-worn apparatus asdescribed herein.

FIG. 4B shows a rear view of the wrist-worn apparatus of FIG. 4A.

FIG. 5A shows a left side view of an example of a wrist-worn apparatus.

FIG. 5B shows a right side view of the wrist-worn apparatus of FIG. 5A.

FIG. 6 shows a schematic diagram depicting placement of a wrist-wornapparatus.

FIG. 7 shows a flowchart of an example operation for receiving andcapturing cardiac signals using a wrist-worn apparatus as describedherein.

FIG. 8 shows a block diagram of a wrist-worn apparatus that may beincluded with any feasible wrist-worn apparatus described herein.

DETAILED DESCRIPTION

Described herein are apparatuses (including devices and systems) andmethods for collection, observation, and/or monitoring of cardiacinformation. For example, described herein are apparatuses that areconfigured to be worn on a subject's wrist as a wristwatch, smartwatch,etc. in a first configuration and converted to a second configuration inwhich the apparatus is held by the subject against the subject's chestto capture and/or record three cardiac lead signals. These cardiac leadsignals may be orthogonal and contain sufficient information tosynthesize, derive, or determine conventional 12-lead cardiac data.These handheld devices may also perform one or more auxiliary functions,such as a timekeeping or watch function. By performing an auxiliaryfunction, a patient may easily wear or carry the cardiac monitoringdevice, thereby enabling cardiac monitoring at a variety of locations,many beyond clinical settings.

In some examples, cardiac data associated with the three cardiac leadsignals may be transmitted to a separate device for monitoring oranalysis. For example, the three lead cardiac data may be transmitted toa remote unit (server, processor, computer, tablet computer, or thelike) for processing, synthesis (to conventional 12-lead data), and/ordisplay to a clinician. In other examples, the handheld device mayinclude a processor that can perform the processing and synthesis andinclude a display to provide information to a user.

FIG. 1A illustrates one example of a system 100 for cardiac signaldetection and/or diagnosis. The wrist-worn apparatuses described hereinmay perform any or all of the functions illustrated and described withrespect to FIGS. 1A-1B, 2A-2D, and 3A-3B, but may be configured asdescribed herein. The system 100 may include a device 2 that includesone or more electrodes mounted, disposed, or coupled to the device(e.g., a housing 3). In FIG. 1A, a user (e.g., subject, patient orclinician) may capture and/or record cardiac signals (in some casescapturing and recording at two or more different times), and thehandheld device 2 may process three orthogonal cardiac leads to comparethe different times (e.g., baseline vs. assay time). A processor (notshown) of the handheld device 2 may further determine if the resultingdifferential cardiac lead signals (differential with respect to the twoor more times the cardiac signals are recorded or “captured”) indicatesthat a possible cardiac problem is present and can alert the user. FIG.1B shows a view of another example of the system 100 including thehandheld device 2 incorporating built in electrodes for cardiac signalacquisition, mounted directly on a housing 3 of the handheld device 2and a remote processor (e.g., a personal computer (PC)) 4 connected viaa telecommunication link to the handheld device 2.

The device 2 may further incorporate cardiac signal recording circuitryincluding one or more amplifiers, analog to digital converters (ADCs)for amplifying the cardiac signals detected by the electrodes, and datastorage (e.g., memory) for storing cardiac signal data. The device 2 mayalso include communication circuitry operating on GSM, WWAN, Wi-Fi orany other feasible telecommunication standard for communication with aremote processor 4. In this manner, the device 2 may transmit recordedor captured cardiac signals or cardiac lead information to one or moreremote devices such as the remote processor 4. The device 2 may includevisual and/or audio circuits or devices (e.g., display, monitor,speaker, etc.) for communicating diagnostic information to the user.

The device 2 may communicate with the remote processor 4 via integratedcommunication circuitry. The remote processor 4 may, in turn,communicate with the handheld device 2 via an integrated communicationmodule. The remote processor 4 may be equipped with diagnostic softwarefor processing the received cardiac signals, producing diagnosticinformation and for transmitting the diagnostic information back to thedevice 2 for communicating the diagnostic information to the user via aspeaker producing characteristic sounds or voice messages or in the formof graphical information via the visual and/or audio circuits or devicesincluded with the device 2. As a consequence, the system 100 may becapable of performing automated detection of a cardiac condition on thebasis of a 3-lead system and may not require interpretation of thediagnostic information by a specialist. Alternatively, instead of theremote processor 4, the device 2 may include a microprocessor within thehousing 3 for processing the captured or recorded cardiac lead signalsand producing diagnostic information.

FIGS. 2A, 2B and 2C show front, back and axonometric views,respectively, of an example of a device 200. The device 200 may be anexample of the device 2 of FIGS. 1A and 1B. FIG. 2A shows the front viewof the device 200 in a recording position as held by a patient. Thedevice 200 may include the housing 3, and electrodes C, D, and Gdisposed on a front surface 6. FIG. 2B shows the back view of the device200. As shown, electrodes A and B may be disposed on a back surface 5 ofthe housing 3. FIG. 2C shows the axonometric view of the device 200.This view shows the electrodes C, D, and G disposed on the front surface6 of the housing 3 and electrodes A and B disposed on the back surface 5of the housing 3. In some examples, the G electrode may be referred toas a ground electrode. The device 200 may also include additionalelectrodes to contact the patient hidden in this view.

The housing 3 of the handheld device 200 may incorporate the electrodesA, B, C, D, and G arranged in such an arrangement that enables recordingof three electrocardiogram (ECG) lead signals. For example, theelectrodes A and B mounted on the back surface 5 of the device may makecontact with the chest of the patient in when the device 200 is in arecording position. The electrodes, A and B (which may be referred to aschest electrodes), are preferably arranged to cover a distance (e.g., beseparated by) greater than at least 5 centimeters (cm), and preferablygreater than about 10 cm. One reason for having such a spatialarrangement is to achieve a distance greater than an approximatediameter of the heart muscle which is needed to provide and/or improvepossible lead orthogonality.

In addition to the two chest electrodes A and B, the handheld device inthis example may include two other electrodes C and D, mounted on thefront surface 6 substantially parallel and opposite to the back surface5. These electrodes, C and D, may be used to capture or record cardiacsignals from the patient's hands by pressing with fingers of the leftand right hands respectively. The fifth electrode G may serve as agrounding electrode and is mounted on the front surface 6 for pressingwith a left-hand finger.

Referring back to FIG. 2A, there is shown a view of one example of thedevice in a recording position. For operation, the patient may place hisleft hand so that patient's index and middle finger contact electrodes Cand G respectively. Further, the patient may position and press thehandheld device 200 against his chest so that the chest electrodes A andB contact his chest in the manner shown in FIG. 2D for producing tightcontact between chest and the device. This may produce enough pressurefor holding the device against the chest. Simultaneously, a finger ofthe right hand (or any other part of the right hand) may press theelectrode D mounted on the front surface 6 of the housing 3.

Referring back to FIG. 2D, there is shown a front view of the device 200placed against the patient's body in a recording position according toone example of the invention. In an optimal recording position, thecenter of the device 200 may be placed closely above the center of theheart so that the chest electrodes A and B are approximately on themidclavicular line (the vertical line passing through the midpoint ofthe clavicle bone), and the lower chest electrode B is at about thelevel of the lower end of the sternum.

The example in FIG. 3A shows a simple electrical scheme for obtaining acentral point (CP) signal by connecting the electrodes of both hands viaa simple resistive network consisting of two resistors. Similarly, FIG.3B shows an electrical scheme for obtaining the CP signal usingbuffering and averaging via operational amplifiers. The CP signal may beused to provide an arbitrary reference (e.g., a reference voltage) thatmay be used in conjunction with signals from the electrodes A, B, C, D,E, and G to generate three orthogonal cardiac lead signals. In someexamples, the three orthogonal cardiac lead signals may be used togenerate a conventional 12-lead ECG signals. One method to transform thethree orthogonal cardiac signals is described at least in U.S. patentapplication Ser. No. 17/494,806 and incorporated by reference herein.

As described herein, the apparatus (e.g., device, system, etc.) 200 maybe implemented as a watch. Thus, the watch may be worn by the subjectand may be used whenever convenient to capture, record, and/or transmitcardiac signals or data. In this manner, the apparatus 200 may be awearable cardiac diagnosis device. One such implementation is describedwith respect to FIGS. 4-6 .

In general, the use of a resistive network is optional. Any of theapparatuses described herein may be used without a resistive network ormay not include a resistive network as describe. For example, theapparatus may be configured to record two (or more) channels, and storeand/or transmit the recorded channels for direct analysis by a physicianand/or software, or for further processing.

FIG. 4A shows a front view of a wrist-worn apparatus 400. As depicted inFIG. 4 , the wrist-worn apparatus 400 may be implemented as a wrist-wornwatch. The wrist-worn apparatus 400 may include a first wrist bandportion 410, a housing 420, and a second wrist band portion 430. Thefirst wrist band portion 410 may be removably coupled to the secondwrist band portion 430 by a clasp, latch, etc., thereby enabling thepatient to wear the wrist-worn apparatus 400 on the subject's wrist. Thewrist-worn apparatus may be configured to be slightly biased (as shownin FIGS. 5A-5B) in the wrist-worn configuration or may be relativelyflat in the linear (unlatched) configuration. The biased, slightlyconcave configuration shown in FIGS. 5A-5B may help maintain contactwith the apparatus against the patient's chest.

The housing 420 may include a display 421 that may be used to provideinformation to the patient. For example, when operating in a first mode,the display 421 may provide conventional watch related information suchas time of day, date, and other chronometer information. In someexamples the apparatus may be configured to provide instructions onusing the wrist-worn apparatus to record ECG signals. For example thewrist-worn apparatus may be configured to operate in a second mode torecord ECG signals, and the display 421 may provide information relatedto ECG information, including instructions on how to position and usethe apparatus to record ECG information. For example, the display 421may show images regarding the placement of the wrist-worn apparatus 400on the patient's body. In another example, the display 421 may showusage instructions and/or information regarding the capture and analysisof a patient's cardiac lead signals. In some examples, the housing 420may enclose a speaker (not shown) that may provide acoustic informationto the patient. For example, the speaker may provide audible directionsregarding the usage or placement of the wrist-worn apparatus 400. Inanother example, the speaker may provide tones associated with capturingcardiac lead signals.

In some examples, the housing 420 may enclose a transceiver 422 that maybe configured to communicate with any other feasible device. Forexample, the housing 420 may enclose a Bluetooth transceiver that may beused to communicate cardiac signal data with any feasible Bluetoothenabled device, such as a smart phone, or the like. In another example,the housing 420 may enclose a Wi-Fi transceiver that may be used tocommunicate cardiac signal data with any feasible Wi-Fi enable deviceincluding computers (laptop computers, desktop computers, tabletcomputers, or the like), Wi-Fi access points, smart phones, etc. Instill another example, the housing 420 may enclose a cellulartransceiver that may be used to communicate cardiac signal informationvia any feasible cellular network.

In some examples, the cardiac data (e.g., captured cardiac lead signals)may be analyzed on a remote processor (such as the remote processor 4 ofFIG. 1B). For example, the cardiac data may directly or indirectly betransmitted to the remote processor 4 using the transceiver 422 includedwithin the housing 420. In some other examples, the housing 420 mayenclose a processor 423. The processor 423 may analyze any capturedand/or recorded cardiac lead signals. For example, any operations thatmay be performed by the remote processor 4 may be performed by theprocessor 423. In any of the apparatuses described herein the circuitryand/or processor may be integrated into the strap(s), rather than, or inaddition to, a housing.

The first wrist band region 410 may include a first electrode 411 and asecond electrode disposed (shown in FIG. 4B) on the inside surface ofthe first wrist band portion 410 and the second wrist band portion 430.The inside surface may refer to the surface configured to be wornagainst the wrist when in the first, wrist-worn configuration, which mayalso be configured to be held against the chest in the ECG collectionconfiguration. The second electrode may be on the second wrist bandregion 430 or it may be on the housing 420 (not shown). The thirdelectrode 431 and a fourth electrode 432 may be disposed on the oppositeside of the apparatus, such as the opposite (outward-facing) sides ofthe first wrist band region 410 and the second wrist-band region, and/oron the housing. In some examples, portions of the patient's body maycontact the first electrode 411 and the second electrode 431 in orderfor the processor 423 to determine three orthogonal cardiac leadsignals. For example, a right finger may be placed in contact with thethird electrode 412 and a left finger may be placed in contact with thefourth electrode 432.

FIG. 4B shows a rear view of the wrist-worn apparatus 400. As mentioned,the third electrode 412 may be disposed on the first wrist band region410 opposite the first electrode 411. Similarly, the fourth electrode432 may be disposed on the second wrist band region 430 opposite thethird electrode 431. In some uses, the wrist-worn apparatus 400 may beplaced on the chest of the patient thereby placing the second electrode412 and the fourth electrode 432 in contact with the chest. In someexamples, first electrode 411 may be separated from the second electrode431 by a distance of at least 5 centimeters (cm). In some cases, theseparation distance may be at least 10 cm so that the second electrode412 and the fourth electrode 432 may span a distance larger than atypical heart muscle. Thus, the first electrode 411 and the secondelectrode 431 may receive electrical signals from the patient's heart.

The patient may be guided by the wrist-worn apparatus 400 to correctlyplace the wrist-worn apparatus 400 on an optimal position on the chestso that the first electrode 411 and the second electrode 431 may captureand/or detect cardiac signals from the patient's heart. For example, thewrist-worn apparatus 400 may provide one or more images on the display421 and/or provide audible instructions through a speaker 425 to guideplacement of the wrist-worn apparatus 400 on the patient. In someexamples, a back of the housing 420 may act as an additional oralternative electrode. For example, the back of the housing 420 mayperform the functions associated with a ground electrode.

The housing 420 may enclose circuitry 424 to capture and/or recordcardiac lead signals from one or more of the first, second, third, andfourth electrodes 411, 431, 412, and 432 respectively. In some examples,the circuitry 424 may capture and/or record cardiac lead signals from aground electrode (such as the back of the housing 420, or any of thedescribed electrodes performing the function of the ground electrode.Thus, the first electrode 411, the second electrode 431, the thirdelectrode 412, and the fourth electrode 432 (and in some cases thehousing 420) may be coupled to circuitry 424 to capture and/or recordcardiac lead signals. In some examples, the circuitry 424 may includeany number of feasible filters, amplifiers, analog-to-digitalconverters, memory, and the like to capture and/or record cardiacsignals.

In some examples, the processor 423, in conjunction with the circuitry424, may receive data from one or more coupled electrode and determineone or more sets of orthogonal three-lead cardiac signals. In someexamples, the processor 423 can record sensor data from one or moreelectrodes, three-lead cardiac data, or synthesized (e.g., derived)12-lead cardiac data (e.g., 12-lead electrocardiogram (ECG)information). The processor 423 in conjunction with the transceiver 422may transmit cardiac data (including orthogonal three-lead cardiacsignal data) to another device for further processing or analysis. Insome examples, the processor 423 or a separate device may processcaptured or recorded cardiac data to synthesize conventional 12-leadcardiac data. That is, the three-lead cardiac signal data may includeall the information sufficient to synthesize conventional 12-leadcardiac data.

In some examples, the processor 423 can process cardiac signal datacollected through electrodes and the circuitry 424 and determine thatplacement of the wrist-worn apparatus 400 is incorrect. The processor423 may also instruct the user to correct placement of the wrist-wornapparatus 400 and/or correct placement of fingers on any feasibleelectrode. For example, the processor 423 can provide the instructionsto the user through the speaker 425 and/or a display.

FIG. 5A shows a left side view of a wrist-worn apparatus 500. Thewrist-worn apparatus 500 may include a first wrist band region 510, ahousing 520, and a second wrist band region 530. The wrist-wornapparatus 500 may be an example of the wrist-worn apparatus 400 of FIGS.4A and 4B. Thus, the first wrist band region 510 may be an example ofthe first wrist band 410, the housing 520 may be an example of thehousing 420, and the second wrist band region 530 may be an example ofthe second wrist band 430.

As shown, the first wrist band region 510 may include a first electrode511 and a third electrode 512. The second wrist band region 530 mayinclude a second electrode 531 and a fourth electrode 532. FIG. 5B showsa right side view of the wrist-worn apparatus 500. The wrist-wornapparatus 500 includes the first wrist band region 510, the housing 520,and the second wrist band region 530. In some examples, the back of thehousing 520 may perform as a fifth electrode.

The first, second, third, and fourth electrodes 511, 531, 512, and 532may be electrically coupled to circuits or the like within the housing520 by one or more conductors (wires, or the like) included with, orembedded within the first wrist band 510 and the second wrist band 530.

In some examples, the wrist-worn apparatus 500 may operate in a firstmode as a watch or any other similar or feasible time keeping device(e.g., a chronometer). In some cases, the first wrist band region 510may be removably coupled to the second wrist band region 530 to form acontinuous loop with the housing 520. When so coupled, the wrist-wornapparatus 500 may be easily and comfortably worn on a user's orpatient's wrist. Although the strap (“wrist band”) shown in FIGS. 4A-4Band 5A-5B includes two parts, each connected to the housing, in someexamples a single strap or band is included and may be coupled to ahousing or the housing may be integrated into the strop or band. Inexamples having a single strap or band, the apparatus may include afirst region and a second region that are both on the same band orstrap.

The wrist-worn apparatus 500 may operate in a second mode to capture oneor more cardiac signals through one or more electrodes. In the secondmode, the wrist bands may be uncoupled from each other and thewrist-worn apparatus may be placed on the patient's chest. In thismanner, the second electrode 531 and the first electrode 511 (andoptionally the housing 520) may be placed in contact with the chest ofthe patient. In some examples, the second electrode 531 may be separatedfrom the first electrode 511 by a distance of at least 5 cm and in somecases by a distance of at least 10 cm (e.g., between 5 cm and 14 cm,between 6 cm and 12 cm, between 8 cm and 12 cm, etc.), particularly whenthe wrist-worn apparatus 500 is placed on the patient's chest.

In the second mode, a processor (included within the housing 520) maycapture, record, and in some cases analyze the cardiac signals. Forexample, the processor may synthesize conventional 12-lead ECGinformation from cardiac signals received by one or more electrodes ofthe wrist-worn apparatus 500. Alternatively, or additionally, thewrist-worn apparatus 500 can transmit data associated with the capturedcardiac signals to another device thereby enabling remote monitoringand/or analysis of the patient's cardiac health. In some examples, thedevice receiving the data may synthesize the conventional 12-lead ECGinformation.

FIG. 5B shows a right side view of the wrist-worn apparatus 500. Thewrist-worn apparatus 500 includes the first wrist band region 510, thehousing 520, and the second wrist band region 530. The first wrist bandregion 510 includes the first electrode 511 and the second electrode512. In this example, the second wrist band region 530 includes thesecond electrode 531 and the fourth electrode 532. In FIGS. 4A-4B and5A-5B multiple adjacent electrodes are shown on the inner surface 529and outer surface 540, though in some examples on single electrodes areused. Alternatively or additionally, multiple electrodes may be used andthe overall system may be filtered

FIG. 6 shows a schematic diagram 600 depicting placement of a wrist-wornapparatus 610 as described in FIGS. 4A-4B and 5A-5B. The wrist-wornapparatus 610 may be placed on (over) the patient's 620 left chest suchthat the electrodes contacting the chest are approximately straddlingthe patient's heart. Fingers from the patient's hands may be placed incontact with electrodes. For example, a finger from the patient's lefthand 630 may be placed in contact with one electrode on a wrist band andanother finger from the patient's right hand 640 may be placed incontact with another electrode on a different wrist band.

In some examples, the wrist-worn apparatus 610 may guide the patient inoptimizing the placement of the wrist-worn apparatus on the patient 620.For example, a processor within the wrist-worn apparatus 610 may receiveone or more cardiac signals, particularly from electrodes in contactwith the patient's chest. The wrist-worn apparatus 610 may analyze thesesignals and determine that the placement of the wrist-worn apparatus 610is incorrect. In response, the wrist-worn apparatus 610 may displayplacement instructions or, in some cases, may provide audibleinstructions to guide the patient to correct the placement of thewrist-worn apparatus 610.

The form of the apparatus shown in FIGS. 4A-4B, 5A-5B and 6 is just oneexample of a wrist-worn apparatus. In some examples the wrist-wornapparatus does not include a watch body having a watch face but is asingle continuous strap. The strap may include the first portion andsecond portion as described herein. In some examples a body may beincluded but may not be configured as a watch body.

FIG. 7 shows a flowchart 700 of an example operation for receiving andcapturing cardiac signals using a wrist-worn apparatus. The wrist-wornapparatus may be the wrist-worn apparatus 400 of FIGS. 4A and 4B, thewrist-worn apparatus 500 of FIGS. 5A and 5B, the wrist-worn apparatus610 of FIG. 6 , or any other feasible wrist-worn apparatus. In FIG. 7 ,the operation begins as wrist-worn apparatus detects cardiac signals inblock 702. For example, the wrist-worn apparatus may detect cardiacsignals for a set of three-lead cardiac signals through includedelectrodes. The cardiac signals may be detected through one or moreelectrodes. If no cardiac signals are detected, then the operation maycontinue to periodically (or continuously) check to see if any cardiacsignals are detected. On the other hand, if cardiac signals aredetected, then in block 704, the wrist-worn apparatus may read and/orprocess the ECG (cardiac) signals. In some examples, the detection ofcardiac signals may cause the wrist-worn apparatus to transition from afirst mode (e.g., a time keeping mode operating as a watch, for example)to a second mode to capture cardiac signals. Alternatively oradditionally the user may select a control or input to indicate that themode is switching from timekeeping, etc., to detecting an ECG signal. Bywaiting until cardiac signals are detected, the wrist-worn apparatus maysave power by operating in a low-power watch mode instead of arelatively higher power mode to capture and/or process cardiac signals.

In block 704, the wrist-worn apparatus can read (capture) ECG (cardiac)signals. For example, the wrist-worn apparatus can capture cardiacsignals through one or more included electrodes. Next, in block 706 thewrist-worn apparatus can provide signal processing to the capturedcardiac signals. For example, the cardiac signals may be buffered,amplified, digitized (through one or more analog-to-digital converters,for example), or the like. In block 708, the processed cardiac signalsmay be stored in a memory.

Next, in block 710, a 12-lead ECG information may be synthesized fromthe processed cardiac signal data. This operation may be optional, asdenoted by dashed lines in FIG. 7 . Thus, the wrist-worn apparatus mayinclude a processor that may synthesize (derive, determine) 12-lead ECGinformation from processed cardiac signal data, including processedcardiac signal data that may include three-lead cardiac signal data. Inblock 712, the wrist-worn apparatus may display 12-lead ECG informationdata on a display. In some examples, the display may be separate fromthe wrist-worn apparatus.

Returning to block 708, the wrist-worn apparatus may wirelessly transmitthe processed cardiac signal data in block 714. For example, thewrist-worn apparatus may transmit captured three-lead cardiac signaldata directly or indirectly to one or more remote devices. In block 716,the remote devices can synthesize a 12-lead ECG information. The 12-leadECG information may be analyzed or monitored by a clinician to ascertainthe cardiac health of the patient.

FIG. 8 shows a block diagram of an example wrist-worn apparatus 800. Thewrist-worn apparatus 800 may include electrodes 810, processing circuits815, a wireless transceiver 820, a processor 330, a memory 840,input/output devices 850, and time keeping circuits 860.

The electrodes 810 may be included within the wrist-worn apparatus 800,or external to the wrist-worn apparatus 800, such as disposed on one ormore wrist bands (not shown). The electrodes 810 may be coupled toprocessing circuits 815. The processing circuits may include buffers,amplifiers, analog-to-digital converters, or the like to capture and/ordigitize cardiac signals received by the electrodes 810. The processingcircuits 815 may be coupled to the processor 830.

The wireless transceiver 820, which may include circuits and/or deviceto provide wireless communications with any other feasible device, iscoupled to the processor 830. In some examples, the wireless transceiver820 may include Bluetooth, Wi-Fi, cellular, or any other feasiblewireless communication circuits. In some examples, the processor 830 maytransmit captured cardiac signal data through the wireless transceiver820 to other devices that may, in turn, synthesize conventional 12-leadECG information data therefrom.

The input/output devices 850, which is coupled to the processor 830, mayinclude visual and/or audio devices to display or provide audiblefeedback or information to a patient or clinician. The time keepingcircuits 860, which are also coupled to the processor 830, may be usedto provide time of day information that may be displayed on a display,such as one included within the input/output devices 850.

The processor 830, which is also coupled to the memory 840, may be anyone or more suitable processors capable of executing scripts orinstructions of one or more software programs stored in the wrist-wornapparatus 800 (such as within memory 840).

The memory 840 may include a data storage region 842 that may be used tolocally store cardiac signal data collected from the electrodes 810. Forexample, the electrodes 810 may receive cardiac signals that areprocessed by the processing circuits 815 and then stored in the datastorage region 842.

The memory 840 may also include a non-transitory computer-readablestorage medium (e.g., one or more nonvolatile memory elements, such asEPROM, EEPROM, Flash memory, a hard drive, etc.) that may store thefollowing software modules: a Cardiac signal synthesis module 844 tosynthesize 12-lead ECG information. Each software module includesprogram instructions that, when executed by the processor 830, may causethe wrist-worn apparatus 800 to perform the corresponding function(s).Thus, the non-transitory computer-readable storage medium of memory 840may include instructions for performing all or a portion of theoperations described herein.

The processor 830 may execute the cardiac signal synthesis module 844 togenerate or synthesize conventional 12-lead ECG information from cardiacsignal data that may be stored in the data storage region 842. Forexample, orthogonal 3-lead cardiac signal data may be captured throughthe electrodes 810 and then stored in the data storage region 842.Execution of the cardiac signal synthesis module 844 may cause theprocessor 830 to retrieve some or all of the cardiac signal data storedin the data storage region 842 and generate 12-lead ECG informationbased thereon. One method to transform the three orthogonal cardiacsignals into 12-lead ECG information is described at least in U.S.patent application Ser. No. 17/494,806 and incorporated by referenceherein.

Optionally, any of these apparatuses may include sensing for cardiacevents when the device is worn on the wrist, in order to trigger analert to the user or a caregiver (e.g., doctor, nurse, technician,family member, etc.) to use the device to take readings as describedabove. For example, as shown in FIG. 8 , any of these apparatuses mayinclude wrist-worn monitoring using one or more sensors. In someexamples the sensors may be the electrode(s) 810 used for measuring fromthe chest, while in other apparatus examples separate, dedicated sensors846 may be used. For example, one or more Photoplethysmography (PPG)sensors on the apparatus, such as on the strap and/or housing may beused. The processing circuits 815 may be configured to process signalswhen the device is worn on the wrist of the patient and may periodicallyor continuously monitor the patient based on the signal(s) sensed. Insome examples the signals may be detected from sensors on differentportions of the inner surface of the strap and/or housing (e.g., watchhousing) to determine which sensor(s) are detecting the presence of thepatient and a cardiac signal. For example, if PPG is used, the PPGsignal may detect the heartbeat and the regularity of the heartbeat maybe determined.

With either electrical (e.g., electrodes) or PPG signals, a time-domainanalysis of the signal(s) may be done to extract features that mayindicate cardiac problems. The apparatus may use extracted features todetermine if the patient is in or is likely to be in, cardiac distress.Determination of diseased vs. healthy states may be performed by theprocessing circuits 815 and/or processor 830, based on e.g., decisiontrees, discriminant analysis, logistic regression, etc.

In some examples the apparatus may provide continuous (or periodic)monitoring and recording as described above and may denoise the signaland/or may preprocess (e.g., filter) the signal or use the raw signal todetermine heart rate variability (HRV). If the HRV exceed a threshold,which may be adjusted for the patient specifically or may be generic,the apparatus may trigger the alert.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein and may be used toachieve the benefits described herein.

The process parameters and sequence of steps described and/orillustrated herein are given by way of example only and can be varied asdesired. For example, while the steps illustrated and/or describedherein may be shown or discussed in a particular order, these steps donot necessarily need to be performed in the order illustrated ordiscussed. The various example methods described and/or illustratedherein may also omit one or more of the steps described or illustratedherein or include additional steps in addition to those disclosed.

Any of the methods (including user interfaces) described herein may beimplemented as software, hardware or firmware, and may be described as anon-transitory computer-readable storage medium storing a set ofinstructions capable of being executed by a processor (e.g., computer,tablet, smartphone, etc.), that when executed by the processor causesthe processor to control perform any of the steps, including but notlimited to: displaying, communicating with the user, analyzing,modifying parameters (including timing, frequency, intensity, etc.),determining, alerting, or the like. For example, any of the methodsdescribed herein may be performed, at least in part, by an apparatusincluding one or more processors having a memory storing anon-transitory computer-readable storage medium storing a set ofinstructions for the processes(s) of the method.

While various embodiments have been described and/or illustrated hereinin the context of fully functional computing systems, one or more ofthese example embodiments may be distributed as a program product in avariety of forms, regardless of the particular type of computer-readablemedia used to actually carry out the distribution. The embodimentsdisclosed herein may also be implemented using software modules thatperform certain tasks. These software modules may include script, batch,or other executable files that may be stored on a computer-readablestorage medium or in a computing system. In some embodiments, thesesoftware modules may configure a computing system to perform one or moreof the example embodiments disclosed herein.

As described herein, the computing devices and systems described and/orillustrated herein broadly represent any type or form of computingdevice or system capable of executing computer-readable instructions,such as those contained within the modules described herein. In theirmost basic configuration, these computing device(s) may each comprise atleast one memory device and at least one physical processor.

The term “memory” or “memory device,” as used herein, generallyrepresents any type or form of volatile or non-volatile storage deviceor medium capable of storing data and/or computer-readable instructions.In one example, a memory device may store, load, and/or maintain one ormore of the modules described herein. Examples of memory devicescomprise, without limitation, Random Access Memory (RAM), Read OnlyMemory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives(SSDs), optical disk drives, caches, variations or combinations of oneor more of the same, or any other suitable storage memory.

In addition, the term “processor” or “physical processor,” as usedherein, generally refers to any type or form of hardware-implementedprocessing unit capable of interpreting and/or executingcomputer-readable instructions. In one example, a physical processor mayaccess and/or modify one or more modules stored in the above-describedmemory device. Examples of physical processors comprise, withoutlimitation, microprocessors, microcontrollers, Central Processing Units(CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcoreprocessors, Application-Specific Integrated Circuits (ASICs), portionsof one or more of the same, variations or combinations of one or more ofthe same, or any other suitable physical processor.

Although illustrated as separate elements, the method steps describedand/or illustrated herein may represent portions of a singleapplication. In addition, in some embodiments one or more of these stepsmay represent or correspond to one or more software applications orprograms that, when executed by a computing device, may cause thecomputing device to perform one or more tasks, such as the method step.

In addition, one or more of the devices described herein may transformdata, physical devices, and/or representations of physical devices fromone form to another. Additionally or alternatively, one or more of themodules recited herein may transform a processor, volatile memory,non-volatile memory, and/or any other portion of a physical computingdevice from one form of computing device to another form of computingdevice by executing on the computing device, storing data on thecomputing device, and/or otherwise interacting with the computingdevice.

The term “computer-readable medium,” as used herein, generally refers toany form of device, carrier, or medium capable of storing or carryingcomputer-readable instructions. Examples of computer-readable mediacomprise, without limitation, transmission-type media, such as carrierwaves, and non-transitory-type media, such as magnetic-storage media(e.g., hard disk drives, tape drives, and floppy disks), optical-storagemedia (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), andBLU-RAY disks), electronic-storage media (e.g., solid-state drives andflash media), and other distribution systems.

A person of ordinary skill in the art will recognize that any process ormethod disclosed herein can be modified in many ways. The processparameters and sequence of the steps described and/or illustrated hereinare given by way of example only and can be varied as desired. Forexample, while the steps illustrated and/or described herein may beshown or discussed in a particular order, these steps do not necessarilyneed to be performed in the order illustrated or discussed.

The various exemplary methods described and/or illustrated herein mayalso omit one or more of the steps described or illustrated herein orcomprise additional steps in addition to those disclosed. Further, astep of any method as disclosed herein can be combined with any one ormore steps of any other method as disclosed herein.

The processor as described herein can be configured to perform one ormore steps of any method disclosed herein. Alternatively or incombination, the processor can be configured to combine one or moresteps of one or more methods as disclosed herein.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising” means various components can be co-jointlyemployed in the methods and articles (e.g., compositions and apparatusesincluding device and methods). For example, the term “comprising” willbe understood to imply the inclusion of any stated elements or steps butnot the exclusion of any other elements or steps.

In general, any of the apparatuses and methods described herein shouldbe understood to be inclusive, but all or a sub-set of the componentsand/or steps may alternatively be exclusive, and may be expressed as“consisting of” or alternatively “consisting essentially of” the variouscomponents, steps, sub-components or sub-steps.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical valuesgiven herein should also be understood to include about or approximatelythat value, unless the context indicates otherwise. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. Anynumerical range recited herein is intended to include all sub-rangessubsumed therein. It is also understood that when a value is disclosedthat “less than or equal to” the value, “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “X” is disclosed the “less than or equal to X” as well as “greaterthan or equal to X” (e.g., where X is a numerical value) is alsodisclosed. It is also understood that the throughout the application,data is provided in a number of different formats, and that this data,represents endpoints and starting points, and ranges for any combinationof the data points. For example, if a particular data point “10” and aparticular data point “15” are disclosed, it is understood that greaterthan, greater than or equal to, less than, less than or equal to, andequal to 10 and 15 are considered disclosed as well as between 10 and15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11,12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

What is claimed is:
 1. A wrist-worn apparatus configured to measure ECGsignals, apparatus comprising: a first wrist band portion including afirst electrode on an inner side of the first wrist band portion and athird electrode on an opposite side of the first wrist band portion; asecond wrist band portion including a second electrode on an inner sideof the second wrist band portion and a fourth electrode on an oppositeside of the second wrist band portion, wherein the first wrist bandportion and second wrist band portion are configured to be coupledtogether to form a continuous loop worn on a subject's wrist, and arefurther configured to be uncoupled, spread apart, and positioned on thesubject's chest so that the first electrode and the second electrode arein contact with the subject's chest and separated by 6 cm or more tomeasure bioelectric signals from the subject's chest, wherein the thirdelectrode is configured to measure bioelectric signals from thesubject's right hand and the fourth electrode is configured to measurebioelectric signals from the subject's left hand; and a processorconfigured to process three orthogonal cardiac leads derived from thefirst, second, third and fourth electrodes, wherein the apparatus isconfigured to operate in a first mode to be worn on the subject's wristwhen the first wrist band portion is coupled to the second wrist bandportion and is further configured to operate in a second mode to capturethe bioelectric signals when the first wrist band portion is uncoupledfrom the second wrist band portion and the wrist band portions areplaced on the subject's chest.
 2. The apparatus of claim 1, furthercomprising a resistive network forming a central point in a sagittalplane through the subject's chest passing between the third and fourthelectrodes when the first wrist band portion and the second wrist bandportion are held against the subject's chest, wherein the threeorthogonal cardiac leads are formed from the first, second, third andfourth electrodes and the central point.
 3. The apparatus of claim 2,further comprising a housing enclosing the resistive network andprocessor, wherein the housing is positioned between the first wristband portion and the second wrist band portion.
 4. The apparatus ofclaim 1, wherein the third electrode is configured to be placed incontact with a finger from the subject's first hand and the fourthelectrode is configured to be placed in contact with a finger from thesubject's second hand, the subject's second hand being different thanthe subject's first hand.
 5. The apparatus of claim 1, wherein theprocessor is configured to record and transmit the three orthogonalcardiac leads.
 6. The apparatus of claim 1, wherein the processor isconfigured to synthesize conventional 12-lead electrocardiogram (ECG)information from the three orthogonal leads.
 7. The apparatus of claim6, wherein the processor is housed within a housing positioned betweenthe first wrist band portion and the second wrist band portion.
 8. Theapparatus of claim 1, further comprising a display configured to displaya time output when the first wrist band portion and the second wristband portion form a continuous loop worn on a subject's wrist.
 9. Theapparatus of claim 8, wherein the display is configured to indicate anorientation of the apparatus when held against the subject's chest. 10.The apparatus of claim 1, further comprising a clasp configured tosecure the first wrist band portion to the second wrist band portionaround the subject's wrist.
 11. The apparatus of claim 1, furthercomprising a wireless transmitter configured to transmit data from thethree orthogonal cardiac leads.
 12. The apparatus of claim 1, whereinthe processor is configured to output instructions to capture one ormore sets of three-lead cardiac signals when the first wrist bandportion and second wrist band portion are spread apart.
 13. Theapparatus of claim 1, wherein the processor is further configured tomonitor the subject's cardiac signal while the wrist-worn apparatus isworn on a wrist and to emit an alert if the subject's cardiac signalexceeds a threshold.
 14. The apparatus of claim 1, wherein the apparatusoperates as a watch in the first mode.
 15. A wrist-worn apparatusconfigured to measure ECG signals, apparatus comprising: a first wristband portion including a first electrode on an inner side of the firstwrist band portion and a third electrode on an opposite side of thefirst wrist band portion; a second wrist band portion including a secondelectrode on an inner side of the second wrist band portion and a fourthelectrode on an opposite side of the second wrist band portion, whereinthe first wrist band portion and second wrist band portion areconfigured to be coupled together to form a continuous loop worn on asubject's wrist, and are further configured to be uncoupled, spreadapart and positioned on the subject's chest so that the first electrodeand the second electrode are in contract with the subject's chest andseparated by between 6 and 14 cm to measure bioelectric signals from thesubject's chest, wherein the third electrode is configured to measurebioelectric signals from the subject's right hand and the fourthelectrode is configured to measure bioelectric signals from thesubject's left hand; a housing coupled between the first wrist bandportion and the second wrist band portion comprising a display face; aresistive network with the housing and forming a central point in asagittal plane through the subject's chest passing between the third andfourth electrodes when the first wrist band portion and the second wristband portion are held against the subject's chest, wherein threeorthogonal cardiac leads are formed from the first, second, third andfourth electrodes and the central point; and a processor configured toprocess the three orthogonal cardiac leads derived from the first,second, third and fourth electrodes and to synthesize conventional12-lead electrocardiogram (ECG) information from the three orthogonalcardiac leads, wherein the apparatus is configured to operate in a firstmode to be worn on the subject's wrist when the first wrist band portionis coupled to the second wrist band portion and is further configured tooperate in a second mode to capture the bioelectric signals when thefirst wrist band portion is uncoupled from the second wrist band portionand the wrist band portions are placed on the subject's chest.
 16. Amethod of detecting a cardiac signal from a subject, the methodcomprising: wearing an apparatus in a first mode on the subject's wristwhen a first wrist band portion of the apparatus is coupled to a secondwrist band portion of the apparatus; removing the apparatus from thesubject's wrist; operating the apparatus in a second mode when the firstwrist band portion is uncoupled from the second wrist band portion, theoperation comprising: placing the first wrist band portion and thesecond wrist band portion of the apparatus against the subject's chestso that a first electrode on an inner surface of the first wrist bandportion is in contact with the subject's chest and a second electrode onan inner surface of the second wrist band portion against is in contactwith the subject's chest, wherein the first electrode is separated fromthe second electrode by 6 cm or more; placing a finger of a first handagainst a third electrode on an outer surface of the apparatus and afinger of a second hand against a fourth electrode of the apparatus;measuring electrocardiogram (ECG) information from the first, second,third and fourth electrodes; processing the ECG information; andoutputting the processed ECG information as an ECG signal.
 17. Themethod of claim 16, wherein measuring the ECG information comprisesmeasuring three orthogonal leads using a resistive network forming acentral point in a sagittal plane through the subject's chest passingbetween the third and fourth electrodes when the first wrist bandportion and the second wrist band portion are held against the subject'schest, wherein three orthogonal cardiac leads are formed from the first,second, third and fourth electrodes and the central point.
 18. Themethod of claim 17, wherein processing the ECG information comprisesprocessing the three orthogonal cardiac leads to synthesize conventional12-lead electrocardiogram (ECG) information, further wherein outputtingthe processed ECG information as an ECG signal comprises outputting theconventional 12-lead ECG information.
 19. The method of claim 17,wherein further comprising transmitting the three orthogonal cardiacleads from the apparatus to a remote processor to process the threeorthogonal leads.
 20. The method of claim 16, further comprisingremoving the apparatus from the subject's wrist by uncoupling a latch onthe apparatus.
 21. The method of claim 16, wherein placing the finger ofthe first hand against the third electrode comprises placing the fingerof the first hand against the third electrode on an outer surface of thefirst wrist band portion and placing the finger of the second handagainst the fourth electrode comprises placing the finger of the secondhand against the fourth electrode on an outer surface of the secondwrist band portion.
 22. The method of claim 16, wherein placing thefinger of the first hand against the third electrode comprises placingthe finger of the first hand against a housing comprising a display,wherein the housing is between the first wrist band portion and thesecond wrist band portion.
 23. The method of claim 16, whereinprocessing the three orthogonal leads comprises processing using aprocessor housed within a housing positioned between the first wristband portion and the second wrist band portion.
 24. The method of claim16, further comprising display a time output on a display of theapparatus when the apparatus is worn on the subject's wrist.
 25. Themethod of claim 16, further comprising instructing the subject, via anoutput from the apparatus, how to hold the apparatus against thesubject's chest.